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How long is a climb leg in a step-climb cruise flight segment allowed to take, according to regulations (FAA/EASA)?
I am working on a trajectory optimisation program for commercial, large aircraft, in which I want to incorporate realistic air traffic control regulations. One of the constraints I want to incorporate is that of ATC requiring step-climb cruise at specific flight levels.
Specifically, the hemispheric rule, though not universal, is a good example of how air traffic is managed by enforcing that westbound flights take even flight levels (FL020, FL040, etc.), whereas eastbound flights take odd flight levels (FL010, FL030, etc.).
So, aircraft should fly at one of these flight levels during cruise, when in level flight, thus resulting in a step-climb cruise, as opposed to a continuous-climb cruise profile. E.g., if an aircraft flying east starts its cruise at FL330, it would want to increase its altitude at some point for increased fuel efficiency. If cleared by ATC, it should climb to FL350 (maybe even FL370, if feasible), and so on.
My question is; are there any restrictions on how long the climb part between each of the level portions can take, at maximum (in terms of distance, time, or some other measure), and if so, what is the specific FAR/JAR or CS25 chapter that mentions it?
One could imagine that if such regulations aren't imposed, the climb segment in between level steps could take up so much time, theoretically, that effectively the cruise would still be continuous-climb. Although this is probably not too much of a problem in real life, it is a problem in my trajectory optimisation program. I.e., without proper bounds on the duration/length of this in-between climb leg, the solution always tends towards a continuous-climb solution by making the level flight portion short and the climb portion large.

The FAA's IFR handbook sheds some light on what they expect (page 2-48)

If the pilot receives the term “climb at pilot’s discretion” in the
  altitude information of an ATC clearance, it means that the pilot has
  the option to start a climb when they desire and are authorized to
  climb at any rate, and to temporarily level off at any intermediate
  altitude as desired, although once you vacate an altitude, you may not
  return to that altitude. When ATC has not used the term nor imposed
  any climb restrictions, pilots should climb promptly on acknowledgment
  of the clearance. Climb at an optimum rate consistent with the
  operating characteristics of the aircraft to 1,000 feet below the
  assigned altitude, and then attempt to climb at a rate of between 500
  and 1,500 fpm until the assigned altitude is reached.

Its somewhat contradictory, first they say you can climb at any rate you want but then they say in the absence of any specific instructions you should climb at an "optimum" rate to within 1000 feet of your assigned altitude and then climb between 500fpm and 1500fpm.
This is specifically spelled out in the AIM with more or less the same language

When ATC has not used the term “AT PILOT’S DISCRETION” nor imposed any
  climb or descent restrictions, pilots should initiate climb or
  descent promptly on acknowledgement of the clearance.Descend or climb
  at an optimum rate consistent with the operating characteristics of the
  aircraft to1,000 feet above or below the assigned altitude, and then
  attempt to descend or climb at a rate of between 500 and 1,500 fpm
  until the assigned altitude is reached. If at anytime the pilot is
  unable to climb or descend at a rate of at least 500 feet a minute,
  advise ATC.

Interestingly this adds the note that if you can not climb at 500 f/min then you should alert ATC. I would take this to be a minimum climb rate.
There is at least one permitted case of the drift climb that I know of. The Concorde operated above all other commercial traffic and aside from the SR-71 there really was no one else up where they were. As such once they passed a specific floor they were allowed to drift up freely as they burned fuel. This was, as far as I know unique to their operation and specifically permitted. They had a lot of other specific addendums due to their unique design.

That is a very clear comment, thanks. One thing that seems especially contradictory to me in the IFR handbook is that you are allowed to temporarily level off, thereby lowering your RoC to 0 fpm. This doesn't agree with the implicit minimum climb rate of 500 fpm. Then again, I reckon real-life applications wouldn't benefit from such strict regulations.

One of the mental skills a controller has to have is the ability to anticipate whether conflicts could arise as a result of the instructions he/she gives to traffic, and this would include the parameters around a climb instruction.  So the type of clearance or instruction given would take into account the potential for conflicts using what you might call rules of thumb that include ample safety fudge factors.

@Sam, would you please quote the full part about the pilot being allowed to temporarily level off during an IFR climb?  This needs context, because generally no, if you are climbing to an assigned altitude you cannot arbitrarily just level off.

@MichaelHall I think he is referencing the line "and to temporarily level off at any intermediate altitude as desired" from the IFR manual (in my above quoted passage)

@Dave - is that a direct quote then?  (I don't see it on page 2-28 of the linked document.)

@MichaelHall sorry its page 2-48 I referenced incorrectly, but yes its a direct quote

Sure enough, there it is.  Very important though to include:  "If it is necessary to level off at an intermediate altitude during climb, advise ATC."  That is the context I was looking for, and it always applies whether or not the term "pilot's discretion" is used.

Indeed that was the quote I was referring to. My apologies for not including it directly.

To address what's discussed in comments...
The East/West rule governs cruise altitude.  When you're climbing to or descending from your cruise altitude, those rules don't apply.  ATC obviously has to consider opposite direction traffic when they contemplate where/when to issue those climb & descent clearances, but for the pilot, that's just a matter of a few minutes before the clearance gets issued.
So let's say I'm on a westbound flight.  I know that I'll be cruising at FL300, 320, 340, 360, 380, or 400 (since my aircraft can't go above 410 and any flight that's long enough to think about a step climb won't be cruising at an altitude as low as 280 or below).  Typically, there will be some optimum altitude that I'll climb to, given the winds and my initial weight.  Let's say that the FMC says that my ideal altitude for "right now" is 34,300'... I can't cruise there, so I'll climb to FL340.  Time passes, and that ideal cruise altitude increases.  After a while, I'll be better off at FL360.  That point doesn't occur when the ideal passes FL350; you're less efficient 1000' above the optimum altitude than you are 1000' below it.  Let's say, for simple math, that the break even point is 500' above optimum is the same burn (per mile) as 1500' below.  So when my FMC optimum altitude is 35,500, I'll request FL 360.  And when ATC has a clear path -- no oncoming traffic at FL 350 -- they'll clear me up to FL360.  And a couple of hours later, that process will repeat when I'm ready to step up to FL380.
As far as a model, if you assume 500 FPM average climb from 340 to 360 (or any other step), that's four minutes of climbing for each step, and that's probably a pretty reasonable estimate.  In most cases, the aircraft will climb faster than that, but when those steps happen a couple of hours apart, is the difference between 2.0 or 3.1 minutes vs 4 minutes really significant for the model?  If it is, then you'll need far more detailed performance data for specific aircraft you're modeling than any rule of thumb can give you.  But, I'd suspect that for most purposes, assuming 4 minutes (or somewhat less) for the step climb to the next even (or odd, in the case of eastbound flights) is probably a workable assumption that will give you a reasonable approximation of what aircraft typically burn in such a scenario.

Thanks, indeed this summarises and clarifies some of the points discussed in the comments. Especially your last paragraph is what I intended to get out of this question; the RoC requirement poses an upper bound on the time to climb to a new FL. Because I got this answer from Dave's response first, I left his as the accepted answer. You're right, 2 or 4 minutes makes no difference to the model, but without the upper bound of 4 minutes, the optimisation algorithm pushes the climb towards solutions with very small rates of climb, thereby not modelling realistic ATC-compliant trajectories.

ATC does not specifically require a step climb.  The only reason they would hold you at an altitude lower that your intended final cruise altitude would be conflicting traffic, or airspace constraints.  For example, a departure controller will clear you up to the top of their sector, but you will need to contact a center controller to be cleared higher.
The only real requirement related to duration of climb is that ATC requires you to report if unable to maintain your climb at a minimum of 500ft/minute.  If you report unable to meet this they may have you level off, but there is no minimum time required at any intermediate level offs before reaching final cruise altitude.
My understanding is that some airliners will step climb for reasons of fuel efficiency at certain weights.  (and/or because of climb rate)  However, step climbing for this reason wouldn't be regulatory or imposed by ATC, it would be an airline policy, or requested by the pilot.

Okay, then my understanding of the hemispheric rule is probably somehow off. I found that under visual (VFR) or instrument flight rules (IFR), one has to stick to certain flight levels according to the aircraft's heading, whenever in controlled airspace. Isn't step climbing a logical consequence of this rule, then? And if not, could you explain how these rules (hemispheric rule and allowing continuous climb) aren't contradictory?

@Sam - FYI, it is actually the aircraft's magnetic course that determines the hemispheric rules.  (in case heading is adjusted for wind and you are crabbing 355 but drifting 005...)  Your understanding of the hemispheric rules seems correct, however, I'm not sure how this relates to step climbing.  If I file IFR westbound at FL 240, why would ATC need me to level off on the way up if I can maintain 500FPM all the way up to 240?  (presuming traffic is no factor)

So basically the climb duration is related only to the informal requirement of maintaining a minimum RoC at 500 fpm. Isn't it strange that those climb requirements aren't concretised in a specific regulation? As to your last point, it seems to me that the hemispheric rule is related to step climbing, because the level "steps" at which the aircraft flies are defined by those FLs defined by that rule. Indeed, if you can maintain 500 fpm all the way up, there's no need to level off in between; the only thing limiting a continuous climb would be not meeting a minimum RoC, it seems.

FYI, the "requirement" to report if unable to meet 500FPM is actually in the AIM, so it isn't regulatory in the sense that the CFRs are.  But I'm still not quite understanding how you could think that step climbing is a logical consequence of the hemispherical cruising rules.  What made you first think that you would need to level off for some random period of time at 2000' intervals?  I assume you have flown in an airplane at some point in your life?  Did it do this?

Ah I now see where I didn't make myself clear. I didn't think you'd have to stop at 2000' intervals when climbing. Rather, I assumed that due to the hemispheric rule, you wouldn't be allowed to climb gradually (and slowly) during cruise. From a trajectory optimisation point of view, this gradual climbing as you burn fuel would be most fuel-efficient. However, it seems that this is inhibited by the requirement to fly at a specific flight level. As for my background; I haven't piloted, but have flown in an airplane as a passenger and I study aeronautical engineering.

Ok, I understand you now.  You do have to level off at some point though, versus flying a fully optimized parabolic arc of some sort.  The exception would be if you are flying a "bingo" emergency fuel profile.  Our profiles would have us climbing at full power so some altitude based on distance to a divert, very minimal time at altitude, then an idle descent.

Normally it‘s handled that way in RL (oc only when there is no conflicting tfc): pilot departing, requests FL410. We will clear him to FL410 without issuing a rate restriction. This means we really don’t care if the average rate will be 1000fpm or 50fpm. If the rate is really low it occasionally happens that the aircraft will level during climb (also in like FL376). This is a normal procedure with the A320 family, without giving a rate restriction it will climb with a high rate and then level for 10secs before climbing again. If necessary we coordinate the aircraft climbing with next sector

If it is necessary that the aircraft keeps a good climb rate we will say so. For example: „UAL123 climb FL390 at 500ft/min or greater“. In case we know the Aircraft performs quite well this can also be up to 1500ft/min occasionally when necessary to climb above traffic


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What are some of the differences between piston engines used in aircraft and automobiles?
What are some of the differences between piston engines used in aircraft and automobiles?  It seems aircraft engines are much more expensive, I imagine some of that cost must be due to the more extreme environment (temperature, air density, roll angle) that an aircraft engine is expected to run in.
In particular:

Are aircraft engine parts expected to be less likely to fail?
What is done to allow the engine to function at extreme temperatures / altitudes / air densities?
Do changes have to be made to allow a piston engine to function while upside down (in a roll)?
What components are different on an aircraft vs automotive piston engine (magnetos vs. spark plugs, oil system)?

The engine in a typical light airplane (say a Cessna 172 or a Piper Cherokee) has a lot in common with the engine in a classic 1960s VW Beetle (Type 1): Both engines are horizontally opposed four-stroke four-cylinder spark ignition gasoline engines. Their parts even have similar metallurgy, and broadly similar failure rates.
In fact if you remove the gearbox and install a magneto ignition system you basically have one of several "Volkswagen aircraft engines" that are popular in the experimental market, and have proven to be very reliable if well-maintained.
Certificated aircraft engines (the Lycoming and Continentals you would find in our hypothetical Piper or Cessna) have a few other features not found on a Volkswagen engine: They have dual ignition systems (two magnetos, two spark plugs per cylinder) for redundancy in case one fails, and an oil sump designed to hold at least twice the capacity of oil needed for safe operation. They typically also have a manual mixture control to allow the pilot to lean the fuel/air mixture as they climb (the VW Beetle generally didn't get too high above sea level, and when they did the local mechanic could adjust the mixture in the garage because those cars would probably stay at a relatively high altitude for most of their life - aircraft have an annoying habit of climbing and descending a lot, so either a manual mixture control or an altitude-compensating carburetor is necessary).
So what accounts for the price difference? Three things: FAA Certification, Volume, and Liability.
FAA Certificated engines cost quite a bit of money: The manufacturer needs to thoroughly document their design and manufacturing practices, and ensure the engine meets the design requirements and can pass the tests described in FAR 33. Doing (and documenting) all of this to the FAA's satisfaction is not a small burden, and it adds to the cost of the final product.
Volume is the next problem: As a reward for complying with Part 33 and getting your engine certified you now have the opportunity to sell your engine. To a very small market. There are far fewer piston aircraft than cars, and although piston aircraft engines are often "worn out" over the life of an airframe most owners overhaul their engines rather than replacing the whole engine outright. As a result the volume of new engine production is relatively low (and with relatively brisk competition in the overhaul market the manufacturer isn't even guaranteed a substantial amount of that business). As with any other product, when volume is small price goes up to allow a profit.
Liability is the last (and probably largest) factor affecting pricing: Jane Q. Pilot is flying along in his brand new just-off-the-production-line Cessna with her two kids and the family dog when the engine fails. She is unable to make a successful landing, and everyone dies, whereupon her bereaved and distraught husband John immediately sues the mechanic who last worked on the plane, Cessna (who made the airframe), and Lycoming (who made the engine).
Being ready to deal with this kind of high-profile and high-cost event requires a substantial legal team (the cost of which is built into each engine sold), and as the manufacturer is accepting a substantial risk the price gets bumped a bit more to provide a balancing reward (profit).

So to answer your bullet-pointed questions which I largely ignored in the explanation above:

Are aircraft engine parts expected to be less likely to fail?
We may have this expectation given the price tag, but in reality they're probably about as reliable as any other well-maintained air-cooled 1960s engine design.  A modern car engine has a number of design and technological advantages over the typical piston aircraft engine, and if we equipped them with dual independent ignition systems and gave them the kind of maintenance aircraft engines get they may well beat aircraft engines in terms of reliability. (Of course a modern car engine also weighs a lot more than a typical aircraft engine, so some money would have to be spent making it lighter without sacrificing that reliability.)
What is done to allow the engine to function at extreme temperatures / altitudes / air densities?
Surprisingly little: The addition of a mixture control for the carburetor, dual independent ignition systems, and a healthy weight consciousness pretty much covers it.
Do changes have to be made to allow a piston engine to function while upside down (in a roll)?
Yes (the fuel and lubrication systems for need to be designed to handle zero / negative G loads for an extended period of time), but your typical piston aircraft engine isn't designed to function while upside down: Aerobatic aircraft engines are a slightly different beast, and they cost a little more than their non-aerobatic counterparts.
What components are different on an aircraft vs automotive piston engine (magnetos vs. spark plugs, oil system)?
The biggest difference between a 1960s VW engine on a classic Beetle and a 2015 Lycoming O-320 is the dual magneto ignition system. The rest of the parts are largely identical, or at least analogous: Spark plugs look like spark plugs, cylinders look like cylinders, carburetors look like carburetors, etc.
Aircraft engines are also designed for component swaps: Cylinders can be easily unbolted and replaced for example, as can the magnetos, the oil pump, the carburetor, the starter, etc.

As a 1960's VW engine veteran I found this answer great because I've often thought the same, but never dared say it in the company of a pilot!

@Dan If I were to build an airplane myself I'd probably go with one of the many VW conversion engines out there - there's very little modified in those designs, and having some experience with VW engines myself I'd honestly fly behind that before some of the newer whiz-bang experimental engines. Even though the newer engines have much more advanced technology I like knowing that I could field strip and reassemble the engine if I were forced to.

Just as an anecdote, HondaJet claims to be using the first newly designed, certificated engines in the last almost 3 decades...

I'd add a couple of quibbles to this.  First, modern cars (pretty much everything built in the last quarter century) don't have carburetors, they have electronic fuel injection.  Second, aircraft carbs don't look much like auto carbs.  They're typically updraft carbs located on the bottom of the engine, while auto carbs are generally downdraft, mounted on top.  Unless you're into '60s British sports cars, which usually have side-mounted SU carbs.

@jamesqf Thousands of small engines are still produced every year with carburetors (lawnmowers, chainsaws, generators), and up through 2011 all NASCAR engines were carbureted as well (they switched to fuel injection in the 2012 season). The position of the carburetor doesn't matter: It's a venturi, a throttle plate, and ports through which fuel is added to the air stream. It could be updraft, downdraft, or side-draft, but the direction the air moves and the plumbing that gets the fuel to the venturi & the mixture to the cylinders doesn't change the core technology.

@voretaq7:  WRT small engines, sure, but the OP was asking about automotive engines.  I don't know of any (in the US) using carbs after the early '90s.  And while the technology of an updraft carb isn't much different from a downdraft, they don't look much alike.

Anedoctal fact: One's my father friend actually build a small plane from scratch and used a 1970 VW beetle engine and it worked

To add some more aspects to voretaq7's answer:
Airplane engines have a very different operating point than car engines. This makes it impossible to simply plug a car engine into an aircraft.

Aircraft piston engines have a max. RPM of 2700. Since they are normally directly coupled to the propeller, a higher engine speed would reduce propeller efficiency. Light aircraft are now fitted with small geared piston engines which reach up to 5000 RPM, but your regular Cessna or Piper will still have the conventional, ungeared engine. Note that the now almost 80 year old Rolls-Royce Merlin was run at 3000 RPM.
Aircraft engines run near their rated performance for hours. Cruise setting is normally between 65% and 75% of maximum power, whereas your regular car engine will see this kind of power setting only for a few seconds at a time. Even when driving on the Autobahn, a car engine will maybe deliver 30% of its maximum power or less most of the time.
Car engines have now plenty of computer control: The ignition point, the mixture and (in some cases) the valve timing can be adjusted for the specific operating point. All these parameters are either fixed, or, in case of mixture, need to be manually adjusted in aircraft.

Points 1 and 3 mean that you cannot compare car and aircraft engines of the same rated power output directly. The higher engine speed and the better adaption translates into much higher power ratings for car engines, but point 2 means that the rated power cannot be delivered when used in an aircraft. If a car engine is run near its rated power for an extended time, it needs a better cooling system. Even then, its components are not designed for these loads and will fail earlier than the corresponding parts of an aircraft engine.
However, due to the much higher number of car engines in operation, we have much better data on the long-time behavior of all parts and much more R&D effort is spent on optimizing them. When run as intended, car engines are now much more reliable than ungeared aircraft engines, even though they have a higher parts count (see point 3 above). Basically, ungeared piston aircraft engines are living museum pieces. The much smaller market size for new aircraft engines is one reason, but the other is the very extensive certification effort which is needed before a newly developed engine can be used in an aircraft. This is necessary to ensure a low failure rate, but has at the same time effectively stopped technological progress to trickle down to aircraft piston engines for half a century.
Electronic ignition systems allow any modern car engine to run upside down, but the oil system needs gravity for the oil to be collected and kept in circulation. For a short time, modern car engines need no modification to run upside down, only the fuel system would need to be adapted.
The temperature extremes for which car engines are tested are more severe than those of airplane engines. Car engines are expected to work at all elevations, so they are designed for similar density variations. Only in extreme cases will an aircraft engine fly higher than the elevation of the highest roads.

Regulation
Lawyers and
Market size

drive the price of aircraft engines up. If they would be expected to work at the environmental extremes that car engines are designed for, they would be even more expensive.

It's my understanding that the Subaru EJ25 (2.5 liter, flat-4, optionally turbo-charged) is very popular in the GA world. It is a fairly modern, electronically controlled motor that will happily run to around a 7500RPM red-line on the ground. What accounts for the differences between those specs and the ones you specify, and how do those who use them in aircraft account for it? (Or do I need to make this a whole new question?)

The controller needs to account for the altitude to adjust the fuel mix, and the (water) cooling needs to be able to keep up

@ratchetfreak, my use of "accounts for" was not not looking for a system to overcome the differences, but why is the EJ25 so popular since it seems to differ so much from Peter's description of an aircraft piston engine. I hadn't thought of your interpretation at all! Seems you hadn't thought of mine. ;)

@FreeMan: Power is proportional to RPM, so the same performance can be gained from less displacement. The engine becomes smaller and lighter, but now needs to be coupled to a gearbox to reduce RPM to something between 2000 and 2500 for propellers. Notice that I sprinkled "ungeared" all over the place in my answer.

Excellent point about the RPM range difference (this isn't a concern for the VW conversions as the Type 1 has a low-revving engine - peak horsepower is around 3,000 RPM and peak torque around 2,000)

@voretaq7: The VW engine is even older than the Lycomings and Continentals, so it should not be a surprise if the RPM range is similar.

@PeterKämpf Indeed, the basic VW engine design dates back to the 1930s (when lower-revving air-cooled engines were very common). If you look at the VW engine's history it also underwent a similar evolution to aircraft engines (Originally shipped with an oil screen, later models had full-flow filters. Originally carbureted, the last few years had mechanical fuel injection. etc.)

I think it's worth pointing out in the answer that VW engines are an exception among automotive engines in being air-cooled.  Most auto engines are liquid-cooled, and most aircraft engines are air-cooled.
Also, you used 'him' to refer to Jane Q Pilot which made me scratch my head upon first read :)

One point that seems to be missing from excellent answers provided so far is carb heat. Carburetor icing is a concern for most if not all carbureted aircraft. The small planes I've flown (Cessna 152/162/172) all have a manual carb heat knob. When you engage it, the engine's air intake is switched over to air that has been warmed by the exhaust. This is designed to melt ice that may be blocking the carburetor or to prevent the ice from forming in the first place.

Carb heat is also used on car engines. Older cars still need a manual change, where the inlet air is ducted over heated engine parts for the winter setting. Modern cars do this automatically.

An aircraft is pulled thru the air by the crankshaft of the engine, and automotive engines aren't designed to have any load pushing or pulling on the crank.
Most if not all aircraft engines have a big thrust bearing to handle this, so auto engine conversions use a reduction drive with a thrust bearing for pulling/pushing the aircraft, or if direct-drive change out the bearings in the engine with one designed to handle the forces involved.
Another major difference between automotive and aircraft engines is the power curve: The Horsepower and Torque value of an aircraft engine run almost parallel lines, whereas in most automotive engines the torque peaks in the low RPM range and horsepower in the high RPM range (for stop-and-go driving, varying speeds, etc.).  An aircraft engine is run more like a stationary application like you would have with a generator or irrigation pump etc.
If an automobile engine were utilized in this fashion it would far exceed the life of most aircraft engines. Why? Air cooled verses liquid cooling. A Liquid cooled engine maintains a constant temperature at all times. An air cooled engine does not. You will not witness a dive from a high altitude in a general aviation aircraft where you chop the power and point the nose at the ground. If you were to try this There is a very good chance you would have some stuck valves when you tried to come back in with the power. Could turn into a bad day.
One last thing: I don't believe a modern well designed engine needs two ignition systems. In all my years of flying I never or have ever heard of any type of ignition failure. When a pilot  is doing a run up before takeoff and does a mag check, the reason you get that 50 rpm drop is because that combustion chamber is not very well designed. You don't need two magnetos.
One thing is certain on any power plant be it auto or aircraft: the less moving parts you have, the better off you'll be. As stated before,the aircraft engine manufactures are held back by the cost of being STC'd from FAA regs. Which in turn hinders development. Many new ideas have come from the home built crowd.

You made a number of excellent points, but on the subject of the need for dual ignition I have to disagree with your assessment: I've heard more than one story of a magneto's timing slipping badly enough to make the engine extremely rough, and the ability to shut off the offending magneto is what allowed the flight to be completed successfully. I'm not sure I'd want to trust my life to a single-engine single-ignition engine...

The dual ignition feature is not merely a redundancy issue, but is a necessary part of full flame front propagation across the wider cylinder bore of aircraft engines. The 50 rpm drop at rich mixture becomes much more noticeable (150-200+ rpm) at leaned out settings. Can fly is very different than producing rated takeoff power. Perhaps there could be a better design, but I'm not aware of one for a big bore IO-550.

Power and torque curves can't run parallel, since the power (in W) is simply the torque (in Nm) multiplied by the speed (in radians per second) (A completely flat torque curve results in a power curve that increases linearly with engine speed) (Torque/power curves for cars are peak values though)

No or very limited emissions control on the aircraft, at least compared to new cars.
Aircraft engines have a rough time with shock cooling.  Cruising at 75% power for hours, then slam the throttle shut and descend, fast.  Shock cooling can crack engines.  Auto engines would not survive very long.  It would be like running an auto engine at full blast on a dyno for a couple hours (as if an auto engine would survive that first step, LOL) and then blasting it with icy fire hose water, like taking hot plate out of oven, toss into icy dish washing water, it shatters.  Even carefully engineered aircraft engines have problems with this.
With respect to fuel pump vapor lock on fuel injected engines, aircraft are about as bad as 80s cars.  Its not really a significant problem under most conditions for most aircraft most of the time, but its sometimes pretty hard on a hot summer day to get liquid gas into the engine to start it.  Ground vehicles work around the problem by having the refinery blend winter or summer gas, but planes can fly from the arctic to the tropics in hours, so its not so simple for planes.
Most aircraft have multiple, usually manually selected, fuel tanks.  Many pilots have died by being overly cavalier about toggling from tank to tank in circumstances where a failure would be fatal.  Very few cars or trucks have more than one gas tank.  Fuel tank piping can be extremely complicated on larger aircraft.
Aircraft fuel is not blended with ethanol so water does not mix with the ethanol like it does in automotive E90 type fuel.  What that means is part of preflight is draining a little (like a cup) of fuel out of the tanks, until no water comes out of the fuel tanks.  You're not suppose to just dump that fuel out on the ground to evaporate, but ...
There is nothing like the ODB-II car standard for planes.  There is no universal plug on all aircraft currently flying where all computer test sets ever made can talk to the engine computer about engine performance.  Such things DO exist for specific engines and specific aircraft but a universal world wide standard does not exist for engine test sets and engine computers in aircraft.
Many aircraft engines are air cooled and its not unusual for performance stats to vary such that the cylinders in back run hotter than the cylinders in front because they sit in air heated by the cylinders in front of them.  People used to water cooled car engines are sometimes surprised by this.
Often variable pitch props are operated by engine oil pressure.  Usually car/truck transmissions use special transmission fluid in their transmissions and power steering/brakes.  I think some (all?) motorcycles use engine oil in their transmissions.  There do exist variable pitch propellers that use hydraulics not engine oil.
Car engines heat the car using circulating water.  Aircraft engines, being air cooled, usually heat the aircraft using a heat exchanger gadget off the exhaust.  Obviously a leak would be rather dangerous.
There is a stereotype that all cars use multi-grade engine oil, and all aircraft use single grade oil.  That is strictly false but true enough, often enough, that it'll be claimed as fact.
(I edit to add in a meta commentary that all 2015 car engines are virtually the same, and the diversity level of aircraft and aircraft engines is dramatically higher.  If you look at a random 2015 car, its engineering is probably roughly identical to any other randomly selected 2015 car.  But seemingly all aircraft are different.  So its easy to talk about car engines but hard to nail down aircraft engines)

Not all cars use liquid coolant - air-cooled cars have similar heat exchanger muffs around their exhaust for winter heat (the VW Beetle from my example being one such vehicle -- Fun VW fact, the heater channels in the Type 1 Beetle are also structural elements of the vehicle)

Another point is that there really is no ECU/PCU in most aircraft piston engines -- this may change as emissions tighten and more manufacturers find FADECs worthwhile, though.

Water-cooled car engines survive shock cooling much better than air-cooled engines. Porsche converted a car engine to aircraft use (the PFM 3200), which had water-cooled cylinder heads. It was very popular for glider tow aircraft, because it allowed a steep dive after release without problems. Car engines are also better in this regard!

For a lot of aircraft, shock cooling is not the problem that a lot of folks make it out to be. See this, and this. In my years of operating and maintaining 320 to 550 sized aircraft engines I can confirm this as well.

My credentials are became the youngest ASE Master Tech when I was 20 years old. I was a mechanic as a sergeant in the US Army, I'm a VW and Audi Master Tech and I modify the spark, fuel, and boost maps in factory ECMs. So I'm really familiar with all the numbers and stuff like that.
Firstly a modern automotive engine is FAR more reliable and efficient than than these aircraft motors  I think that because the EPA isn't all over these guys they haven't had to increase their efficiencies.
I googled the specs on the Lycoming IO 540, and I found it to be kind of pathetic. An 8.7 liter motor, running on 100 octane gas, making 300 hp!?! Compression ratios in the 8s, KILLING fuel too just due to displacement size.
The engine is a mix of old, inefficient, mechanically unreliable parts, that are high maintenance, and then new high performance tech.
For example, it has a direct gear driven overhead camshaft, which robs hp. The valvetrain is ANCIENT and sloppy.
It also runs a fuel injection system that seems to be like the Bosch L and K Jetronic, and CIS Motronic. So, instead of electrical injectors you have braided steel hoses with an orifice in the intake, those go to a fuel distributor, which varies the fuel pressure by modulating a plunger.
VW, Audi, BMW, Porsche, Volvo, ETC ran this system in the 80s and early 90s. When it runs, it runs well, but the fuel pattern isn't very good, and in my experience the nozzles clog and are unable to be cleaned, and the fuel distributor can cost a couple grand with the differential pressure regulator. I'd be VERY interested in seeing the spray patterns of one of them. They generally don't seal well when closed, and they will leak fuel out of the tips, spiddle out rather than a good solid cone shape.
Then, the cylinder heads have only 2 valves per cylinder, so they definitely flow like crap, and depending on their size if they're close to the cylinder bore it can block air flow. The solid tappet camshafts which will flatten if you aren't running high zinc oil. I figured it caused issues, googled Lycoming tappet failure, and what do you know, stories about it along with a roller upgrade.
Running the cam off the crank via a gear causes backlash forces on the bearings and friction parasitic draw of hp, so do flat tappet lifters, the roller lifters are a must imo. The lifters are hydraulic, so they don't need adjustment. One thing scared me, they have you push the lifter down to compress the hydraulic portion and then check the clearance between the lifter tappet and cam. The spec is .028 to .08...You'd think that maybe because they're hydraulic it doesn't matter. Then they state, if you're out of spec you install a longer or shorter pushrod, and to beware because the decreases valve to piston clearances. AKA, if you have a .028 and a .08 gap. Then one of your valves is opening .052 of an inch more than the other. That makes cylinders run unevenly.
HOWEVER one thing good, the engine has molybdenum nickel coating on the cylinder, which reduces piston and ring friction losses, modern cars just started using this. It's been used in racing a long time. Molybdenum is used in those friction reducing oils you see advertised, and they mix it with steel to increase machinability.
Otherwise it's a lot like a Beetle in ALL the bad ways. A split engine case that can leak, removeable pushrod tubes you have to install and seal between the block and head, that leak, uneven cylinder temps.
There's a lot of unknowns too, like how close do they match the factory pistons and rods for weight difference to balance best as possible?
There's NO WAY that engine is more reliable than a modern car that adjusts nearly everything. Soon cars will have electric solenoids to operate the valves, they're already doing it in test cars. This will allow infinitely variable lift and overlap. Once that happens, camshafts are obsolete, along with the timing belt or chain draws.
This motor has way too many metal on metal, non adjustible, wearable parts. You CANNOT make the cylinders make roughly the same hp due to the variations in the pushrods and the heat differences. Anybody who ever was into Beetles knows of the infamous 3rd cylinder meltdown issue. The heat differences between the cylinders cause massively different power output and cylinder balance.
I had many BMW Volkswagen customers with over 300,000 miles on their original engines with no issues and I had decent guys with close to half a million period in eight years of owning a shop I don't think I can say that I ever seen one engine fail that wasn't due to neglect like leaking coolant or not changing the timing belt. Crappy oil.
As far as the torque part numbers people are listening at 60 miles an hour on the freeway the torque load sense by the ECM is usually more like 20 to 25%if you could remap an engine computer like I can it's turbocharged you could call for Boost and stuff down lower then what it's from the factory.
I would find a way to run it off the cams that are the timing belt. But your engines are a joke my sisters 03 Jetta 1.8 Turbo puts out 300 horsepower to the wheels with the stock Turbo. There's no reason to have that big ass V8 that weighs a ton and makes no power. My sister's car gets 20 miles to the gallon when driven nicely.
Your engines have missed out on all the updates that that the car makers are had to do to keep up with the fuel mileage for example running a distributor takes horsepower semi hemispherical combustion Chambers adds horsepower, variable valve timing adds horsepower turbochargers with individual pipes that are separated all the way to the turbo to keep the exhaust pulses group add horsepower.
I don't have my license yet but I've flown a couple times and I was honestly a little scared before I went and took my first lesson but I was astonished at how shitty the technology was on the Cessna 172 and how it basically looks like 1940's automotive technology.
I would run a VW diesel engine or the 2.0 Turbo found in the 05 and up chat is golf's and A3.
The 2.0 T is direct gasoline injection like a diesel because of that and the fuel being injected right at top dead center it allows you to run extreme amounts of boost and ignition timing. There's literally not enough time before the spark event for the gasoline to detonate. Those engines run 16 to 1 air fuel ratio on the highway. They also make them up 210 horsepower stock and with just the tune they make 300 or more.
Quality Automotive electrical systems or absolutely nothing to fear they're redundant about the only thing that will keep one sideline from running would be a bad crankshaft sensor or bad fuel pump comma if you ran joule crankshaft sensors and dual fuel pumps there would be absolutely nothing to worry about.
So, take a look at this here. This is a 1.8t dyno, and a mild one. If you take a 2:1 reduction drive you end up with 200 hp at like 3000 rpm.

I don't get it, maybe it's like the reason truck engines need to be 6, 8 cylinder or more, because they need the increase in bearing size and rod size and strength for load?
But I ran a ton of computation, it doesn't seem to be under a VERY heavy load.
Anyway, Cessna was doing diesel car size motors that seemed fine.
I think it's the old guard not feeling comfortable with computers....I'm supposed to get a settlement soon. Maybe I'll build myself a Cessna with one:)

Diamond makes diesel aircraft engines which are modified Mercedes car engines. The main driver in aviation is not horsepower or efficieny, it is avoiding the unknown.

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text:
What does "S-ILS" signify in an FAA NOTAM?
Consider this NOTAM for LAX from the current list:

FDC 5/0341 LAX IAP LOS ANGELES INTL LOS ANGELES CA. ILS OR LOC RWY 25L AMDT 12C... S-ILS 25L DA 395/ HAT 291 ALL CATS VISIBILITY ALL CATS RVR 2200. ADD NOTE FOR INOPERATIVE ALSF-2 INCREASE S-ILS 25L VISIBILITY ALL CATS TO RVR 4500. EXCEPT WHEN ADVISED BY ATC THAT EQUIPMENT IS DOWN. CONSTRUCTION EQUIPMENT 178 MSL BEGINNING 1399 FEET NORTHEAST OF RWY 25L. 1502052152-1508042152EST

What does S-ILS25L signify, how is it different than just ILS25L, and where can I find the source document?

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text:
What is the scratching sound produced by aircraft on the ground (taxi-in/taxi-out)?
Since I have flown in aicraft as a kid, there was a sound audible when the aircraft is on ground (before taking off or after landing) which is similar to the sound a DJ does when he scratches the disks.
Sorry for the wird example, but I do not know how to explain it better. It is like the scratching of a disk and the sound starts at a higher pitch and it ends at a lower pitch. I am really interested in finding out what it is and why it happens, since I have never been able to find out how it is produced.

Would that sound by any chance be the one in this video?

And if not, could you try to find a video that has it? There are many aircraft videos on youtube, so it's likely some will have it.

@JanHudec Thanks for the link to the other question, I have linked it below in my answer. Should we still mark this question as duplicate though?

That must be the PTU, which sounds like a DJ scratching or a barking dog

This video shows the PTU itself.

There is a variety of sounds an aircraft can produce, some even depending on the type of aircraft you are sitting in. Without any further data or reference, the most likely events that you can hear during pushback, taxi or vacating the runway are:

Cargo Doors being shut and locked
Flaps being extended to take-off position
Flaps being raised after landing

There are many more things that you can hear from the cabin, so without further information, it will be difficult to pin-point.
Another option, if it was predominantly on Airbus aircraft, is the Power Tranfer Unit, which is described to sound like a barking dog or like a drill.
See also this question and the answers:
What is this sound from Airbus aircraft before take off?

Yes indeed! I just found the sound in this video I found on the other post. https://www.youtube.com/watch?v=9aGsXmNjPRw It is the PTU, I needed to know. Thank you very much. @SentryRaven


text:
How do aircraft steer on ground?
How do modern aircraft steer on the ground? Do they have a steering wheel which moves the front wheel (left/right).
I see that there is a Tug vehicle which pushes the aircraft backwards, so the aircraft does not have a reverse gear for sure.
Does the aircraft use the Engine thrust to move forward on the ground or does it have separate motor which propels the wheels?

Hi ViSu, welcome to Aviation.SE! Check out this question for details Taxiing in passenger aircraft.

All of these methods are used.
Nosewheel steering is common on most commercial aircraft using a tiller.  Rudder, differential braking, differential thrust and even motors in the wheels (experimental only as far as I know) are also used, as seen in this video.
Engine thrust is used to move forward but differential thrust might also be used when negotiating tight turns. (Details here)

You beat me to the answer. Want to expand yours by adding a part about electric taxi motors being tested? I intended to mention that.

@Simon Thanks for the answer and the Wiki link. I think the Wiki page answers lot of my queries.


text:
How are flight schedules displayed without ambiguity on DST change days?
Flight schedules are based on the local time of the station of departure or arrival. Twice a year though, this is either ambiguous or impossible. What happens on these boundaries?
Say, for instance, a flight is scheduled for departure daily at 1:30 A.M. This year, DST ends at November 2nd, 2 A.M., meaning the local clock will go from 2 A.M. back to 1 A.M. Will this flight depart on the first 1:30 A.M. or the second?
And the other way round, say next year a flight is scheduled for departure daily at 2:30 A.M. When DST starts, the clock will go directly from 2:00 A.M. to 3:00 A.M. and 2:30 doesn't exist. What happens for this flight?

Flight schedules are based on UTC, at least in all ATC / ATM systems.

Flight schedules are definitely not based on UTC; they are based on local time. The answer to this (good) question isn't really about aviation, but about timetabling. The answer is that the timetable will have a footnote noting and clarifying the ambiguity on that particular day.

@Hugh At the the four airlines I worked for, the flight schedules as maintained by dispatch were all in UTC. It was the responsibility of the individual stations and marketing to translate them to local for public dissemination.

For what it's worth, in 10 years of international flying I never had any trouble caused by DST transitions in spite of the fact that there's a great variety in the datse of implementation between countries. If one was curious what the transition dates were for a given country, there were pages in our Jepp manuals that gave that information.

It's only really ambiguous once a year, when moving from summer time to winter time and the hour is 'repeated' - in this case, departures and arrivals are scheduled in the 'first' instance of the hour: eg if the flight is scheduled 01:30, it will depart 1.5 hours after midnight. The clock will then go back eg at 2am, and the airport will be relatively for one hour with no departures (although, of course, arrivals may still come in)
On the other shift, the hour is 'lost' so the departure takes place later. In practice, no planes are scheduled to arrive or depart in this missing hour, and since almost all nations make the change in the middle if the night when airspace is very quiet and most airports have no departures at all there is virtually no knock-on effect. Arrivals arrive when they arrive, departures are simply scheduled for a 'real' hour, if there are even departures at all at that time of day anyway.
Note that this is only for passenger scheduling - in air traffic control etc all times are Zulu (UTC) which has no ambiguity.
TL;DR: Fall/Autumn, aircraft depart in the "first" instance of the hour. Spring: scheduling works as usual, but with no flights scheduled in the "missing" hour (eg 2-3am)

What does "scheduled in the 'first' instance of the hour" mean? For example if 2:30 UTC and 3:30 UTC both map to the same local time, are you saying that nothing is ever scheduled for 3:30 UTC? Do you have any citation, any evidence for saying that?

Okay, perhaps 'never' is a stretch, as there may be cases where the aircraft has to hit a landing slot elsewhere. Perhaps it's more accurate to say 'rarely' and note that the airline would almost always issue communicate this to the customer and travel agent (eg via an SSR on the PNR)

@JonStory In practice, no planes are scheduled to arrive or depart in this missing hour Can you please provide reference for this statement?

My little experience is that planes tend not to be scheduled for the early hours of the morning. E.g. for trans-Atlantic flights, Europe-to-America (east coast) leaves in the morning so that it arrives in the afternoon or evening, whereas America-to-Europe leaves in the late afternoon or evening so that it arrives in the late morning or early afternoon the next day. Airports are mostly closed at 3 in the morning.

As Chris said, there are very few departures in the early hours anyway. The majority of those that do exist are scheduled to leave in the 'first' hour, before the clocks change. The only time I've seen otherwise is to hit an arrival slot.

@farhan as mentioned it's not a 'never' just a rarely, and there's no rule or guideline ... But have a look at a departure board or call an airline ;)

Oh actually @Farhan I got confused as to which you meant - it's impossible to schedule a flight in the 'missing' hour - it doesn't exist. You can't depart at 2:30am if the clock jumps from 1:59 to 3:00 (or similar), it's physically impossible.

Daylight Savings does not cause ambiguity in flight schedules, even though it may appear to.
Basic Concepts
Before discussing your specific scenarios, let's look at some concepts.

First of all, not all countries observe DST. The ones which do, may not observe it for the same period either. Hence, airlines know if and when the destination region1 observes DST.
A flight's duration does not change because of DST. If an airplane takes 5 hours to reach its destination, it won't take 4 or 6 hours because DST is turned on or off.
Airlines and related entities (e.g. ATC) use times UTC, especially when an airplane is crossing a timezone, to reduce confusion. Pilots and ATC personal are used to follow UTC times without any difficulty. UTC does not observe DST.
When a timezone observes DST, they change the timezone code too. For example, instead of EST (Eastern Standard Time), they'll use EDT (Eastern Daylight Time).
When DST ends, clocks are moved from 3AM to 2AM, not from 2AM to 1AM.

Your Questions
Now, let us talk about the scenarios you mentioned.

If a flight is departing at 2:30AM (time corrected as I mentioned above), it will depart most probably on the first 2:30AM. Flights have their schedules mentioned in UTC as well, so it will not a confusion. As I do not know everything, I have never seen a flight departure time in that particular hour. Would you care to share an example?
If a flight is arriving at supposedly 2:30AM on the day when DST is starting, it will not arrive at 2:30AM but at 3:30AM. Because, as you said, 2:30AM does not exist on that day for that timezone.

Examples
As suggested by fooot, I'm adding an example. This flight is from JFK to AUH.
This first example is on November 1st (when DST is in effect).

Departure    Arrival
EDT 12:40    EDT 01:10
UTC 16:40    UTC 05:10
GST 20:40    GST 09:10 (GST: Gulf Standard Time)

Flight Duration: 12:30

This is the same flight on November 2nd (when DST is not in effect).

Departure    Arrival
ET  11:40    ET  00:10
UTC 16:40    UTC 05:10
GST 20:40    GST 09:10 (GST: Gulf Standard Time)

Flight Duration: 12:30

Footnotes
1: Not all parts of a single country may observe DST. In USA (for example), most parts of Arizona do not observe DST. I agree with them, DST does not make any sense or provide any benefit in today's world.

relevant extra information on DST: https://www.youtube.com/watch?v=84aWtseb2-4 (especially the segment at 5:10 for Arizona)

I think it would be helpful to show an example, with the departure/arrival times in Standard/Daylight/UTC

Schedules as communicated in SSM messages defined in SSIM may be in local time. Regarding 2/3 A.M. Wikipedia claims Daylight saving time starts on the second Sunday in March and ends on the first Sunday in November, with the time changes taking place at 2:00 a.m. local time. With a mnemonic word play referring to seasons, clocks "spring forward and fall back"—that is, in spring (technically late winter) the clocks are moved forward from 2:00 a.m. to 3:00 a.m., and in fall they are moved back from 2:00 am to 1:00 am. ( https://en.wikipedia.org/wiki/Daylight_saving_time_in_the_United_States )

Contrary to your first sentence, it is ambiguous at all: in the case where you say, "it will depart most probably on the first 2:30AM", what if it doesn't and departs instead on the second 2:30AM? Also, 3AM to 2AM, or from 2AM to 1AM, depends on (varies with) the local jurisdiction.

IIRC: EST = Eastern Standard Time and EDT = Eastern Daylight (savings) Time

In UK the switch is from 2am to 1am, because Europe switches at once between 2:00 CET and 3:00 CEST, i.e. at 1:00 UTC.

The autumn switch may be 3am to 2am in your country, but it is definitely from 2am to 1am in the US. And they probably happen on different days too. That’s why UTC is so important to global industries.


text:
Having trouble reading some charts (SBMG-SBLO)
I'm a flight sim user practicing instrument navigation with a short and apparently simple flight, SBMG to SBLO (South America). The distance between the two airports is 49.5 nautical miles (the simulator tells me). My simulator is X-Plane 11. The aircraft is the Cessna 172.
I've flown the mentioned flight a couple of times, but I'm afraid I am making mistakes. There are a couple of questions I'd like to make.
Let's start with this SBMG SID chart (these charts come from AISWEB). The path with red dots is the one I'm following.

(1) You see 096 > on the first 3 nautical miles? Does it mean I should track course 096 on the LON VOR right after takeoff, or is it just the heading I should be on for the first 3 nautical miles? You see, I'm having trouble figuring out what is the reference navigation aid for these headings/radials.
(2) After passing MG123, I start to track the 100 radial on the LON VOR for 47 nautical miles. After 47 miles I switch to the approach chart. Is that correct?

The next chart is a IAC for SBLO. It has a VOR/DME arc.

(3) I am still tracking 100 towards LON, but the nearest entry point for the arc is 090. After 47 nautical miles, I am too close to SBLO to change my course, and it's time to enter the arc already. I feel I missed something.

Well, for one thing that MG123 waypoint is an RNAV waypoint, you cannot fly that route using conventional VOR/DMEs you would have in a Cessna.You need to be at least B-RNAV capable, then track 096 to MG123 followed by 100 to LON (which just so happens to be a VOR but does not need to)

The VOR chart is indeed a conventional one, but it does not match your route. You either need to find a transition of some sort, radar vectors, or self-position (using RNAV) to Ceila which is your Initial Fix

For an Approach, it is perfectly fine to enter the approach anytime between the IAF and the FAF. Typically, this is done by radar vectors from ATC. Otherwise, you should stay above the MSA until you are established on a published leg. Under radar vectors, ATC can get you as close to the airport as the Intermediate Leg. Once established On the Intermediate Leg, you will be lined up for alignment with the Final Approach Leg.

Be very aware of the altitude difference between the MSA and the crossing altitude of your fixes. And, if the IAP has a TAA, you are technically established on the approach if you follow the TAA.

Also, the link you have on your question is to an RNAV SID. You would just follow the magenta line. There is no VOR radial that you need to track. The VOR acts as another GPS waypoint. You are tracking from waypoint to waypoint. You have to switch from RNAV to VOR radio navigation if you want to subsequently fly the VOR Z RWY 13. That means abandoning the SID early. Or, flying all the way to the VOR before starting the published approach.

@Radu094 - Celia is marked IF (Intermediate Fix). If it were an Initial Approach Fix, it would be marked either IAF or IF/IAF.

Thanks for the clarifications. It seems I have a lot to learn before attempting these procedures. Do you recommend any specific material that covers instrument navigation thoroughly?

Just to clarify, it is usually unwise to join the Approach on the Intermediate leg unless you are being radar vectored by ATC due to the difference in altitude between the MSA and the crossing altitudes for the FAF. As far as thorough material...

Pilots Handbook of Aeronautical Knowledge.
Airplane Flying Handbook.
Instrument Flying Handbook.
Instrument Procedures Handbook.
Digital Terminal Procedures  Supplemental.
Aeronautical Chart User’s Guide.
Terminal Procedure Publications.
Flight Navigator Handbook.
Advanced Avionics Handbook.

@crimson_king  - All of these can be found for free online.

@DeanF. ouch, you are right about Ceila , that is an IF. Well, unless there are other parts of the chart missing, it will still work if he reached Ceila at 5000' then descend to Edpud in 2nm..a bit steep for a jet, but a Cessna can do that no problem

alternatively, provided you are cleared that way, once <11 Dme LON you can turn left and establish on the 10 Dme arc, descending from 5000' to 4100', turn right at Ceila( after crossing R297) and just continue on the procedure. It would be legal and doable provided ATC is aware of your intentions and has cleared you

@Radu094 - You are exactly right. The approach can be picked up anywhere before the FAF. I cautioned the OP against it in general unless being radar vectored because the difference in MSA and the FAF crossing altitude could be too great to affect a reasonable and stable descent. This particular IAP should pose no problems for a Cessna, though. I’ve had ATC keep me higher than this for traffic up until the very last possible minute. It was in VMC on a practice procedure, though. Self-vectoring in IMC normally would not be advised without doing the full procedure. VMC is doable, though.

Interesting academic exercise crimson_king. I don’t think you would get cleared for or use this SID/IAP combo. The airports are too close together. You are basically using your destination airport’s NavAid as the beginning/start of your departure. You will overfly the airport before you get to the VOR that starts the procedure. Then, you would have to backtrack out to the arc, using LON as your IAF.
The plate that you referenced is just an instruction on how to get to the start of your departure. There is probably a textual ODP to go with it. If you were in IMC, you would remain under radar vectors and ATC control the entire time. They would probably give you instructions like: Fly runway heading climb and maintain 5000 radar vectors direct D270L cleared the VOR Z Runway 13. This is of course abbreviated since you would have a switch of ATC from tower to approach.
Based on the information provided, For the purposes of simming, your best bet is to:

Take off from the runway of predominant wind.

Remain in the traffic pattern and climb over the airport.

Climb until you are at 5000 feet or more. The reason for this is that the only altitude information I see on the plate are the Minimum Sector Altitude and the Maximum Elevation Figures.

Fly direct to MG123 using RNAV/GPS.

Switch to VLOC/VOR mode

Fly direct to D270L.

Begin your IAP
A second option is to just fly direct to LON using your Nav radio by the shortest route possible. Use MG123 as a fly over reference point. Maintain full throttle at Vx until 5000 feet. Once you are within 12 miles DME of LON. Start your descent down to 4100 feet. Join the arc wherever you happen to enter.

Celia is not marked as an IF/IAF. So, I would avoid going directly there. It would be a perfectly good option if you were being radar vectored and cleared there by ATC.

Thank you for this answer. I will study the information you gave me once I catch up on the required missing pieces of knowledge. It's been a couple of years since my last simulator flight. I'm just a programmer who's enthusiastic about aviation!

@crimson_king - No problem. You might start with US FAA charts and plates first. I am biased for them since they are what I first learned. They seemed to contain more explicit detail in a clearer format than the charts you linked. You can get them free from many online sources like https://skyvector.com/  and  https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/

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text:
Human powered biplane for maximum endurance
Biplanes have lower minimum power and material strength demands. However these slow planes have worse glide ratios and thus distance-based fuel consumption. Today with high performance engines and materials these planes are very niche and monoplanes are the norm.
But these traits seem best for maximizing human-powered flight time. Humans are very weak engines, and the aircraft must have airliner-sized wingspans with an under 100kg weight. This presents an extreme material demand which would be lessened in a biplane design. One could argue that time in the air is more important than speed or distance for the purposes of "having a fun toy to play with". Given these demands, why are human powered biplanes not more common?

From your quoted question: But the main reason is that they're inefficient, and don't really do much that a monoplane can't.

@Jim: It's not doing much. A pedal biplane would fly maybe <10 mph and the pilot could be beaten on foot. It's a toy and a teaching tool, not much more. But the power usage in flight would be lower so more people could fly it and for longer.

Still need to look at the drag from two wings vs from one.

@Jim: The L/D ratio is worse. But the speed is so low (as described in the linked question) that the minimum power is lower even though the thrust must be higher (at constant aircraft weight). At least that's the hope! And presumably the aircraft could be (even) lighter due to the structural advantage.

Question could be improved to better specify exactly what you are seeking to optimize.  Perhaps, "maximum possible endurance till pilot is exhausted, for 20-year-old male in average physical condition"?  Etc you get the idea.  Based on existing HPA history, I doubt the biplane will ever come out the winner, but we can at least get a better idea of exactly what problem we are trying to solve--.  But I don't think that changing the goal from range to endurance (duration) will decisively tip the scales toward the biplane's favor.

@quietflyer: Fixed.

Biplanes originally existed because there was not the material science to make wings long enough to provide enough lift. Due to the juxtaposition of the wings, there is more drag than a single longer wing.

"A pedal biplane would fly maybe <10 mph..."  This is a disconnect.  Heavier than air craft, no matter how light weight or efficient, need to generate lift.  Lift comes from forward speed and <10 mph will barely move a kite, let alone something carrying >100 lbs of meat.

Why not a box-wing aka PrandtlPlane aka Best Wing System? That should be even better than a biplane

@sophit the box-wing gets the fanfare but is it really better? I see it as an attempt to magick away those evil tip vortexes which can't be done for any finite wingspan. What matters is minimum power given material constraints (i.e. longer wings weigh more).

I don't think it is easy to say a priori what is lighter between biplane and box-wing. For sure PrandtlPlane is aerodynamically more efficient, so I'd give a try in the pre-design phase.

@MichaelHall Paragliders stall at around 12mph (20kph) with a comparable wingspan. Pushing this a little lower with a biplane design and airfoil shape isn't out of the question.

@KevinKostlan, can they maintain powered level flight at 12mph, or is that in a descent?  If powered, does the motor put out power comparable to what a person could achieve?  If so, perhaps that's a better solution than a biplane?

@MichaelHall I am not sure. No human powered plane uses a para-motor design that I am aware of. I am going by our first planes that flew, back when engines and materials were weaker, which were biplanes not para-motors.

If I don't remember wrong the very first human powered airplanes had a speed of some 10mph

It's counterintuitive to me that you could better a paraglider's stall speed with a rigid wing of any sort.  Especially one that needs to support the significant weight of "a very weak engine".  Windspeed of <10 mph on the Beaufort scale is merely leaves rustling, and instinctually I cannot fathom flying at that speed.  (let alone enjoying it if I'm huffing and puffing to supply the power...)  Hopefully someone with some math chops can verify my hunch.  Anyway, good luck!

@KevinKostlan - Just a thought about paragliders.  Ripstop nylon and paracord didn’t exist back then either nor did the idea of the ram-air chute.

@jim all materials improved not just fabric and rope. And the pioneers didn't care much about safety features such as ripstops. Although your point stands about the concept and design of the canopy.

I actually flew a human powered biplane called Chrysalis in the late 1970's while a student at MIT. As I remember it, the biplane configuration was driven mostly by the limits of hanger space rather than aerodynamics. https://en.wikipedia.org/wiki/MIT_Chrysalis


text:
How does the nose wheel lock on the Robin DR400 work?
I recently learned that there is a locking mechanism on the nose wheel of a Robin DR-400. This mechanism locks the nose wheel in place when there is no weight on the wheel.
In particular, the wheel will be locked when the plane is in the air. And at landing, when there is weight on the wheel again, it unlocks.
But the nose wheel can also become locked if the center of gravity of the plane is too far back, or may fail to unlock upon landing. In this case, the aircraft becomes uncontrollable, and this can cause a runway excursion.
So I am wondering a few things:

How does this mechanism work?
What is gained by having the nose wheel lock itself? Rather than for instance a spring-like mechanism that just keep the wheel aligned with the plane when the plane is in the air.
Are there other planes with a similar locking mechanism?
Are there planes with a different mechanism to keep the nose wheel from moving in flight?

Here is what the landing gear looks like. It is not retractable and there are fairings on the wheels for better aerodynamics:

I can see the reason if it is retractable (to align it so it fits in the compartment)

@ratchetfreak The landing gear is not retractable.

If I remember correctly, the DR-400 nose gear is prone to shimmy when lightly loaded. Could that be the reason for the lock?

I feel like a locking nose gear could make a crosswind landing pretty dangerous.  A better solution would allow the pilot to lock the gear manually (after take off, and unlock it before landing).

@kjmccarx I hear there have been runway excursions due to this system.

By 'locks', do you mean that it disengages from steering by the rudder pedals or that the wheel itself is actually prevented from spinning?

@reirab it wouldn't make sense if the wheel is "parking-brake locked from spinning" on touchdown. My guess is, if the wheel is pointing straight and the pilot kicks the rudder moments before touchdown, the plane won't yaw immediately on the runway (and likely flip over before it reaches the grass)

@kevin True. I assumed he meant that it disengaged from the rudder pedals, but I just wanted to make sure. I thought that was actually pretty common in GA planes. You're right about the yaw, but, even moreso, it prevents damage to the tire. Touching down while pointing in a direction other than the direction the plane is moving is bad news for the tire.

It looks like the "How do they work?" question has already been addressed pretty well, so I'll answer some of the other parts of the question:

What is gained by having the nose wheel lock itself?

The nose gear is prevented from turning during flight when the rudder pedals are actuated. If the nose gear turned when the rudder was being used in flight, it would add a lot of form drag.
The nose gear remains straight until it touches down on landing, which prevents it from landing sideways in a crosswind landing where the rudder is being used to maintain runway alignment. This allows the pilot to continue to use the rudder inputs to maintain the centerline through the landing roll without damaging the tires or having a sudden yaw in the direction that the tire is pointing when the nose wheel touches down.

Rather than for instance a spring-like mechanism that just keep the wheel aligned with the plane when the plane is in the air.

You mean like a Cessna-style spring linkage, where there is not a hard linkage between the rudder pedals and the nose gear? One advantage of not using the Cessna-style springs is that it's easier to taxi with direct linkages rather than spring linkages. Cessnas have a lag between rudder pedal input and the nose wheel actually turning because of the spring linkages, so you have to give directional inputs ahead of when you actually want to turn. With direct linkages, the nose wheel turns immediately when you push the pedals, which makes taxiing a little easier, especially when you're first learning.

Are there planes with a different mechanism to keep the nose wheel from moving in flight?

Yes. See above for Cessnas. Also, in larger aircraft (e.g. passenger jets and similar,) there are no mechanical linkages to the nose wheel at all and the nose wheel is turned (mostly) by a separate control from the rudder. This control is called a tiller and it's moved by hand instead of by foot. It looks like this:

I found this report by the French accident investigation bureau (BEA) that explains how the mechanism works.

There is a rod attached to the bottom of the damper, and the rod has a protuberance at the top. When there is no weight on the wheel, the top of the rod goes down into a notch that is attached to the mainframe, and locks the wheel. So the wheel can no longer turn around the vertical axis, until the damper is compressed again, and the top of the rod comes out of the notch.

So when the plane takes off, the nose-wheel aligns itself with the mainframe, disengages from the rudder pedals and locks itself in that position. Upon landing, the damper is compressed, the wheel unlocks and can be used to control the plane.


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Where can I get a high-res photo of the RAT from an A320 Airbus?
I'm working on a project regarding the hydraulics system of the A320 airbus.  I can't seem to find a clear Hi-resolution image of a grounded A320 with the RAT extended out.  Anyone know where I can find one? Or if you have one and don't mind me using it for my project, I'd be much obliged!! Thank you!

Airliners.net is the photo directory of aircraft on the internet, a quick search turns up this beauty :) You can also diversify your search to A318, A319 and A321 since it's in principle the same equipment.

Aidyn Iskakov - Almaty Spotting Club
http://www.airliners.net/photo/Air-Astana/Airbus-A320-232/2419974/

(source: airliners.net)

Looks good! Thank you!

@Christina: I'm not sure what type of project you're doing, but photos from airliners.net do have usage restrictions, see http://www.airliners.net/usephotos/ for more details.

Why do you bother looking elsewhere?
AIRBUS has its own Photo gallery!
If you are not lucky enough  and can't find there what you have been looking, ask them kindly (Contacts).
Nothing beats first hand resources!


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Could the Airbus A350 be converted into the role of air tanker / be used for aerial refuelling?
Since the A350 is one of the most efficient jets out there, Is it possible that it can be transformed into a fuel tanker for Aerial refuelling?

sure you could, limiting factor would be fuel weight and position of the tanks

So we shouldn't be too surprised if some military (or Airbus itself) announced that a tanker based on the A350 is being developed.

Especially with all that range (14,300 km) and its impressive low maintenance costs. It just too appealing for militaries

@TaherElhouderi Now what would the range be if it could refuel... itself! ;-)

@Michael just take the difference between MTOW and zero fuel and then divide by default fuel capacity then you have the theoretical range of the all fuel A350

Yes, it could be done. There is an A330 already working as fuel tanker.

Image Source: Wikipedia
Airbus might build a A350 air re-fueler as mentioned here:

Airbus is already offering a tanker version of the A330, and could
  (potentially) upgrade their proposal with an A350 air-refueler. The
  A350 would offer a substantial increase in fuel offload from existing
  tankers, as well as the 767.

The A330 was an "easy" conversion in a sense because there are hard-points on the outer wings. The A330 has the same wing as the A340, but with two instead of four engines - hence there was a good location for fueling hose reels.

...having said that when they were testing it off the coast of Spain in 2011 the refueling boom (which can be seen under the tail) fell off!

While payload, range, and efficiency are important for tankers, militaries have reasons for still using so many 707 variants.
Many of the reasons are similar to Why does the US President fly in an obsolete 747-200? Although making an aircraft into a tanker may be less challenging than making it into a SAM aircraft, it is still a large task. The fuel system needs to be modified and significantly extended, and many other components will be upgraded to military standards. This is a large investment for what is a relatively small fleet of aircraft. It has been more economical to upgrade the aircraft rather than select newer models. Smaller fleets of tankers have been converted from existing aircraft, which is cheaper with older designs rather than the latest and greatest.
Also, like the SAM aircraft, tankers do not see nearly as much flight time as commercial aircraft. The KC-135 fleet stood at an average of 17,000 hours in 2004, with a fatigue life of about 36,000 hours. This means that gains in efficiency are less important, and other costs like maintenance and acquisition are more important.
There have only been orders for about 50 A330 MRTT aircraft. Boeing built 8 KC-767 airplanes, and there are only 3 orders for tanker conversions. The US Air Force is ordering 179 of the KC-46 tankers, with possible further export sales. This overall represents a fairly small market.
Another important requirement is service life. The KC-135 aircraft in the US Air Force have been in service for at least 50 years now. The RAF aircraft are conversions and had a long service life, but not as long as the KC-135. The 767 and A330 aircraft currently being introduced as tankers are newer designs, but still with a long and proven service history. The A350 represents a large step in aircraft design, using composites much more extensively than before. While there is certainly a good amount of confidence that these aircraft will have a long service life, militaries may want to wait until the new design concepts have proven themselves before making expensive orders.

Is runway length also an issue for A350?


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How do I determine the VFR pattern altitude at an airport?
How do I determine the VFR pattern altitude at an airport? Can I find it on a sectional?

In April 2013, the FAA's Charting Group met to discuss this question.  The standard pattern used to be 800 ft AGL, and the Chart Supplement (formerly called Airport/Facility Directory or A/FD) was inconsistent in listing them.  Ultimately they decided:

Chris Criswell, AJV-22, reported that, per ACF recommendation, all traffic pattern altitudes, standard and non-standard, will be added into NASR (the AFD) for all airports. This will be a day forward implementation beginning in July 2014.

Some other places the TPA is recommended to be 1000 feet AGL:
Advisory_Circular AC90-66A

c. It is recommended that airplanes observe a 1000 foot above ground
  level (AGL) traffic pattern altitude. Large and turbine powered
  airplanes should enter the traffic pattern at an altitude of 1,500
  feet AGL or 500 feet above the established pattern altitude. A pilot
  may vary the size of the traffic pattern depending on the aircraft's
  performance characteristics.

The Chart Supplement (A/FD) will typically list the Traffic Pattern Altitude (TPA) if it is non-standard (not 1000 ft/1500 ft AGL)
The FAA's Airplane Flying Handbook says

The traffic pattern altitude is usually 1,000 feet above the elevation of the airport.

Now the Chart Supplement (A/FD) will be the definitive guide!

Hmm, I can't seem to find KAKR's TPA. Would that mean it is 800ft AGL?

@flyingfisch no I think it would be 1000 ft AGL. Everything used to be 800 AGL, but as you can see from AC90-66A and the AFH, if unpublished, it's recommended to do a 1000 ft AGL TPA, which would be 2067 MSL for KAKR.

Ah ok, understood. thank you :)

No, it's not on a sectional. The Traffic Pattern Altitude (TPA) can be found in your A/FD.
Edit: I just double-checked and it's not on all airports in the A/FD. I would assume that if it's not listed it's 1000' AGL, but not sure why it's listed on some and not others. When it is there it'll be on the 2nd line after fuel. It'll look something like this: TPA-1072(1000)

In the UK, this information can be found in the AIS under Aerodrome information - specific and is not printed in charts.
The section on "Flight Procedures" for my local field specifies

Circuits
  (a) Standard overhead join. Variable circuits. Fixed wing circuit height 1000 ft QFE.

For a non-standard traffic pattern altitude, you will be provided an altitude, and if it's a standard traffic pattern altitude (1000' agl), then it will not display an altitude or it will be blank as I've seen before.
e.g. KMBS does not display an altitude but TPA is 1000' agl


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Are there design differences between propellers powered by air (wind-power) and propellers for aviation?
What is the difference of design between a propeller designed to be powered by the wind (i.e. those huge wind power turbine blades) and those designed to be used to propel a plane that are powered by an engine (i.e. a Cessna 172's props)?
(To be clear, I'm talking about one that is powered by the air vs one that powers through the air.)

In essence, nothing.  If you took a propeller from an aircraft and attached it a low friction, high efficiency turbine generator (just as wind turbine blades are) it would act as a generator when placed into wind.  The actual differences are related to the rotation speed, the need to vary pitch and the environments in which they are designed to operate.

Blades of wind turbines, airplanes and helicopters are essentially the same. They are all wings, roughly to do the same job. However, each one is designed or enhanced to do their special job. The differences can be:

Number of revolutions
Wing span
Rate of flow
Tip speed
Density of medium
Material
Load

Turbine blades are designed to move in large volumes of rather slow moving air (usually 10-30 mph, 16-50 km/h) and not create turbulence that fouls the next blade. Aircraft propellers are designed to move high velocity air and avoid the turbulence by moving out of the way.
Wind turbines use blade pitch to adjust the rotation speed and the generated power. Wind turbine's control system adjusts the blade pitch to keep the rotor speed within operating limits as the wind speed changes. In aircraft, blade pitch is usually described as "coarse" for a coarser angle, and "fine" for a finer.

You might want to add that the side of the airfoil with more curvature (normally called the upper side in case of a wing airfoil) points forward in propellers, but backward in impellers (wind turbines).

Please check your answer regarding helis. Heli rotors need to be able to be used in an auto rotation and they therefore  have a very unique design

You missed a fairly important criteria - pitching moment. Helicopter rotors need to have pitching moment of almost zero to prevent the blade from wanting to twist when lift is created. Tailless flying wings sometimes require airfoils with negative pitching moment for stability.

The airfoil profile is also slightly different since, in the case of propellers, the goal is to push the air through. Therefore, the lift produced by the wing and felt by the shaft will produce torque that opposes the rotation. In the other case, the goal is extract energy from the flow going through the turbine. Thus, the lift force is in the opposite direction and helps the shaft rotation. Furthermore, more specific energy (as in per unit mass) can be extracted from the flow than injected into it. This is because, in turbines, the flow is going down the pressure gradient which has a stabilising effect. With a propeller, you're trying to push the flow through an adverse pressure gradient and this tends to enhance flow separation on your blades. Therefore, turbines tend to have higher loads and require thicker profiles.

Airplane propeller has blade angle almost perpendicular to the rotor axis. It normally ranged 0-15 degree. 0 degree will not produce any thrust. More than 15 degree will produce more drag, compare to the trust.
Wind propeller has blade angle almost parallel to the axis. 0 degree mean the blades adjusted exactly parallel to the rotation axis. 15 degree mean, has 15 degree "discrepancy" from the axis.
Angle of Attack (AoA) of propeller and wind turbines are seen from different perspective. AoA of a propeller is seen from the axis itself parallel to the blade. It is just how the bolt corrugation. Meanwhile the AoA of wind turbine blades is seen from the frontal site, parallel to the axis.

This two kinds of bold. The single one is reflecting the AoA of propeller. The corrugation almost perpendicular to the bolt (axis) itself. While the smaller bold in the second picture, showing longer pitch. The longer the pitch until almost parallel to bolt (axis) itself, the more suitable to the wind turbine blade.

There is a BIG difference.  The curve of the blades is reversed.  On a propellor, the leading edge is close to the propellor disk, with the flatter surface towards the rear.  In a turbine, the leading edge points forward (into the wind), with the flatter surface also forward.

I'm a bit confused by your statements. Wouldn't the "leading edge" always "point forward"? If it didn't, it wouldn't be the "leading edge". Can you try a quick re-write to help clarify what you're trying to get across? Maybe include an image or two to show the difference.


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Why do planes have cross-feed switches or circuits?
Why do planes have cross-feed switches or circuits? Are they to move contents of one tank to another (feed the tank) or to supply the engine with fuel from left side to right or vice versa (feed the engine)?

The fuel system in aircraft generally includes a left and right tank within the corresponding wings. Each tank generally provides fuel to the engines on that wing. The crossfeed valve is used to temporarily connect the two sides of the system. This system allows the shortest route for the fuel and keeps the systems separate, so a leak on one side cannot drain the entire system. The crossfeed valve is generally kept shut for this reason. A couple scenarios illustrate when opening the valve might be necessary.
To keep the plane balanced, both wing tanks should have about the same amount of fuel. However, for various reasons, they could become unbalanced. The crossfeed valve allows fuel to flow from the tank with too much fuel to the tank with less fuel.
Another scenario would be the loss of an engine. In a twin-engine airplane, the remaining engine would need to be able to draw fuel from both wing tanks.
Note: especially in larger aircraft, fuel systems can be much more complicated, with multiple tanks in each wing and also in the fuselage. Fuel transfer also becomes more complicated.
Using the 737 as an example, this is the fuel system control panel with the crossfeed switch in the center. With the crossfeed valve open, turning off the fuel pumps on one tank will cause more fuel to be drawn from the tanks on the other side.

The purpose of the cross feed valve or cross feed circuit in the airplanes is to separate the fuels in different tanks, especially in the wings (both left and right wings and fuselage) so that one tank will not affect another in terms of leakage.
The other purpose is for the emergency use. If left fuel pump encounters a problem, the right fuel pump will pump fuel from right tank and supply fuel to both engine one and two, through the crossfeed that is automatically opened. Vice versa to right fuel pump.


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What winglet airfoils are used on the Boeing B737?
I would like to know what airfoils are used for the Boeing 737 winglets.

Aviation Partners Boeing, a joint venture between the two companies, developed the winglets for 737NG, 757 and 767 aircraft.  They are offered in two varieties, a "blended" version, which is where the wingtip is upturned to near vertical and a newer, "split scimitar" version which adds a downward pointing tip as well.  They are made of a composite material with aluminium leading and trailing edges.
Their purpose is not to generate lift, but rather, prevent wingtip vortices (which generate a significant amount of induced drag) from spilling onto the top of the wing.
The design characteristics of the blended winglet are described in US Patent 5,348,253.

They actually do generate lift by increasing the pressure differential at the wingtip. But they do not prevent those mythical "wingtip vortices", and the reason for induced drag is lift creation. All they do is to spread out lift creation over a slightly greater air mass, and the reduction in drag is easily lost with a little sideslip. If you add the additional friction drag, their drag reduction is marginal at best.

You're right, it is impossible to prevent wingtip vortices. Winglets produce a forward thrust inside the circulation field of the vortices to reduce their strength. This, in turn, reduces the amount of induced drag. Airlines using winglets experience fuel burn reductions of up to 5%, hardly a trivial amount.

… using new aircraft with new engines. Please compare apples with apples, and you will see how little winglets actually do. Those 5% come from comparing a 737-300 with a 737-700.

@newmanth, I was asking about the airfoils used in the Boeing winglets, not about what winglets are and who developed them. I am sorry, but your answer is completely irrelevant. Also irrelevant is your reference to Gratzer's patent. Also, your explanation of how winglets reduce induced drag is erroneous. Please, if you are not fully competent in the field, do not provide others with faulty information. Thank you.

@Flanker for continuity they keep using the same airfoils as in the wing.

@PeterKämpf Airbus was able to get 3.5-4% fuel burn netly (including airframe structure weight increase) when retrofitting the A320 http://airinsight.com/2012/11/27/airbus-reports-better-than-projected-sharklet-performance-for-a320/#.VNhZQPmG-AU

@TrebiaProject. You can't really call that a reputable source. In my opinion the A320neo's improved efficiency is mainly due to the engines and it is difficult to prove how much the drag is reduced during all flight stages by the winglets. I see they also mainly experienced the reduction in fuel burn on long-haul flights.

@Jonny that document is describing the improvement of sharklet compared to previous standard. Nothing about NEO is commented. You can find similar information (claiming 4%...) in Airbus press release http://www.airbus.com/presscentre/pressreleases/press-release-detail/detail/airbus-launches-sharklet-retrofit-for-in-service-a320-family-aircraft/ . There are 2 different projects: sharklet modification (in service) and NEO (in Flight Test).

a joint venture between the two companies which companies?

@Federico "Aviation Partners Boeing" => "Aviation Partners" + "Boeing" - the clue's in the name. It's also underneath the logo in the link he posted.


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What do the levels stand for in French Air Traffic Service Levels?
I am planning a flight to Le Touquet (LFAT) in France next week, I've been told that ATC is not open all days so I've checked the NOTAMS. This seems applicable but I'm not sure I'm interpreting it correctly:

LFFA-B3753/14  A) LFAT  LE TOUQUET PARIS PLAGE B) 2014 Aug 01  07:00
  C) 2014 Aug 31  23:59 E) FIRE AND RESCUE HOURS OF SERVICE:
  0700-0900 1500-1800    : LEVEL 2
  0900-1500              : LEVEL 4
  SAUF 15,16,22,23,26-29 : LEVEL 2 ATS HOURS OF SERVICE LEVEL 5 O/R, PPR 24H
  TO OPR  PHONE: +33(0)3 21 05 03 99  FAX: +33(0)3 21 05 59 34 LEVEL 1
  OUTSIDE ATS HOURS OF SERVICE.

I think what this is saying is that it is operating at level 2 ATC hours of service except  (Sauf) on the 15,16,22,23,and 26-29th of August, but level 1 all other hours. I think what this means is that next week on weekdays it will be operating at level 2 hours of service. I also think that level 2 means 07-09:00Z and 15-18:00Z, and during this service level 5 will be offered, but all other times level 1 will be offered.
So I think that if I go on those days listed and times listed the tower will be open, otherwise it will be closed (I'm assuming that's what level 1 means), and that I will need to use French non-towered procedures, including French calls.
I'd like to know if I've made the right interpretation, and if there's a source of information about ATC levels in France. I've scoured the web for a couple of hours with no result.
So what are level 2 hours of service, and what service is provided? What is provided with level 1 ATS?

Would you need to make your non-towered calls in French, or could you do so in English? (Please note, no disrespect of France or it's language intended, I'm curious if pilots there (presumed local on a non-towered day) would be willing/able to use English.)

@CGCampbell I don't know about France, in Germany it's published in the AD section of the AIP (roughly equivalent to the A/FD) which languages are acceptable.

@CGCampbell, they have to be in French. I'm not as worried about making calls in French as much as understanding other calls. I've heard recordings and it's unintelligible to non-native speakers.

This NOTAM concerns the fire and rescue level not the ATS operating hours.
You can find the description of the fire and rescue levels here.
The reference of the ATS hours is to say the level is raised during the opening hours of the ATS.
The ATS opening hours are available on the Visual Access Chart from the SIA. (French service for aeronautical information)
Where you have on last page:

SUMMER 0700 - 1800

Finally for the language, you have to speak French when the ATS is closed.


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What does "reserve take off" mean in engine parameter documentation?
In ATR 72-500 FCOM document I found engine parameters including power settings as "Reserve Take off". What does that mean?

I've edited the question to hopefully make it more clear, feel free to edit or comment if it's not correct.

Can you provide an image or link I the page?

I've seen this mentioned in story (unfortunately in Czech) about flying in Bhutan on ATR-42 (a smaller version of the same aircraft). Basically in most situation it is recommended to use less then maximum rated power to reduce wear of the engine and that setting is marked as “take off” and the maximum rated power is only used in high density altitude (hot and high) conditions or very short runways and is labelled “reserve take off”.
Most other aircraft don't have setting labelled like this, but taking off at less than maximum rated power is common. It is called “derated” or “flex” take-off.

Engines sometimes have a "reserve power range" (or "emergency power") which is only used when the extra power is absolutely needed. This is higher than the "takeoff power" setting that is generally a 5-minute limit on certain parameters for regular takeoffs. ATR is advertising a "reserve take-off torque option" which allows higher power at takeoff. This allows using some of the extra power in difficult takeoff situations. From the materials for the ATR 72-600:

ATR has developed the Take-off at "Reserve Take-off Torque" option to improve take-off capabilities on very short runways or in case of near obstacles.
... ATR and P&WC have jointly worked to provide on request 4.5% higher thermodynamic power at take-off and max continuous ratings. This results in:

Increase of climb gradient in hot and high conditions leading to takeoff weight improvement of around 500 Kg (1,100 lb).

Example: + 500 kg from Bogota airport (8,360ft and ISA+20°C) + 1,000 ft higher one engine out net ceiling.

this is true for a number of aircraft. In the draggy T-6 is we use 36" manifold pressure (AKA "military power") until the wheels & flaps are up, then reduce to 30". The R-44 allows +1.6" MP above MCP for 5 minutes. Full power/rpm in the M20M for takeoff, then reduce to 36"/2400 after the flaps & gear are up.